Drinking straws are known for flavouring or changing the flavour of a liquid passing through the drinking straw. Such drinking straws can impart different flavours (e.g. cocoa, fruit, etc.) to a liquid for example milk.
There are solutions in which the flavouring agent is applied on a portion of the drinking straw and dissolves when this portion is immersed in the liquid. U.S. Pat. No. 3,615,595 describes such flavouring drinking straw. In another embodiment according to U.S. Pat. No. 3,615,595 the flavouring agent is applied on the inner wall of the drinking straw. A disadvantage of this solution is that dissolution of the flavouring agent thereby the flavouring effect is unsatisfactory.
U.S. Pat. No. 5,094,861 discloses an improved embodiment of the flavoured drinking straw of U.S. Pat. No. 3,615,595. Here, carriers of flavouring agent are inserted in the drinking straw. Embodying of this drinking straw is complicated, placing the flavouring agent in the straw requires an elaborate method while the flavouring effect is still unsatisfactory.
The solution proposed in U.S. Pat. No. 6,109,538 differs from the earlier known solutions in that a large sized flavouring object is disposed in the lumen of the drinking straw.
A common disadvantage of the aforementioned embodiments is that proportionally to the dissolution of the flavouring agent placed in the interior of the drinking straw the flavouring effect also decreases and the force required to sip the drinking straw varies significantly especially in the latter solution.
Patent application WO 9851259 is directed to an oral active agent delivery device comprising improved flow controllers.
Here, a hollow tubular member containing the active agent formulation and having a fluid passing controller is placed at one end into a fluid and at a second end into a patient's mouth. The active agent is delivered when the patient sips on the end of the tube. This improved solution prevents leakage of the active agent formulation. This document teaches a number of complicated filtering elements that can be inserted in the drinking straw. On the one hand dosing of the active agent according to this solution is complicated on the other hand it is expensive and flavouring of the active agent may be realized at most by flavouring the fluid in which the device is placed.
Effervescent tablets are also generally used in the food and medical industry. Effervescent tablets are tablets that are designed to break down rapidly when they are placed into water or another liquid, releasing carbon dioxide in the process. The rapid breakdown causes the tablet to dissolve into a frothy or fizzy solution, which property is particularly appealing to younger consumers. Such tablets are also extensively used for the administration of minerals (e.g. calcium, magnesium), vitamins and various drugs (medication).
Effervescent tablets are made by compressing the component ingredients into a dense mass, which is packaged in an airtight container or other airtight packaging since otherwise the tablet would react with humidity (water vapor) contained in the air.
The aim of the present invention is to provide a drinking straw which contains one or more effervescent tablets in order to produce a fizzy drink when a neutral liquid, such as water, is drawn through the straw. The inventors have realized that simply disposing effervescent tablets in any of the prior art filled drinking straws does not solve this problem as the effervescent tablet is not stable once the packaging of the straw is opened, however, consumers often wish to consume a beverage over a longer period of time, or use the same straw more than once. Furthermore, if the effervescent tablet sinks to the bottom of the straw immersed in the liquid then it will dissolve too fast. However, if the tablet floats in the liquid, it will rise to the top of the straw and cause inconvenient foaming in the vicinity of the user's mouth.